For architectural doors, i.e. building doors, electronic door locks are widely used in various types of applications, such as elderly care and nursing homes, hotels, public facilities, etc. One specific type of electronic door locks utilizes mechanical and non-electrical lock cases which are inserted in a door leaf in a conventional manner, i.e. into a recess provided at one edge of the door leaf. The electronic door lock is formed by the lock case as well as an additional electronic lock device which is connected to the lock case e.g. by mounting the lock device on the inner or outer side of the door leaf.
One example of such lock device is described in WO2008101930 by the same applicant. The lock device has an electric motor which is in connection with the lock bolt via a transmission. When the electrical motor is activated the rotational movement is transmitted to the lock case whereby the lock bolt is maneuvered for locking or unlocking the door. Should a user decide to operate the door lock manually, which may be the case if he or she would like to lock the door from the inside, the lock knob may be turned.
In order to have the same mechanical feeling independent of the motor/gear design when turning the key or knob, it is suggested to include a disengagement system. The disengagement is provided by means of a hub having a lug engaging with the axle around which the lock knob rotates. When the lock knob is turned so is the hub.
Once the electrical motor has been activated for unlocking the door, it is important to ensure that the electrical motor is returning to a non-engaging position.
Further, the electronic lock device should preferably be compatible with several different existing lock cases.
Existing lock cases may have different operational schemes; for example, one existing lock case has a lock bolt which is unelastically connected to the lock follower, i.e. to the shaft rotating upon maneuvering the lock knob. For such lock case, when the lock bolt is positioned in an end position (i.e. a locked state or an unlocked state) it is not possible to operate the lock knob further towards that end position, but only towards the opposite end position.
Another existing lock case operates according to a slightly different principle. Rotation of the lock knob (or cylinder key) will cause a retraction of the lock bolt for unlocking the door, however the lock follower is also connected to a spring biased latch, always urging towards it protruded position. For unlocking the door the lock follower is thus rotated for causing an unlocking movement of the lock bolt as well as of the latch.
A yet further lock case existing on the market relies on a different operation principle. The lock follower is maneuvered for unlocking the door causing an unelastic connection with the lock bolt. Once the lock bolt is in its end position unlocking the door, the lock follower may be further rotated in the unlocking direction for causing a subsequent opening movement of a spring-biased latch.
In view of all these examples, it is evident that disengaging or engaging of the motor will depend on the actual end position of the hub relative the ring. For improving the electronic lock device it would thus not only be desirable to reduce the time or distance for engaging the electrical motor, but also to allow the solution to be used for many different existing lock cases. Hence, a versatile electronic lock device would be advantageous which provide efficient and reliable disengaging/engaging of the motor independent of the operation principle of the lock case.